1. Field of the Invention
The present invention relates to a resistor and more particularly to an overcurrent protective wire wound resistor.
2. Description of the Related Art
Resistors are one of the indispensable components for manufacturing all kinds of electronic products and can be generally classified as fixed resistors and variable resistors. Among the fixed resistors, resistors having resistance wires wound around are called wire wound resistors.
With reference to FIG. 5, a conventional wire wound resistor has a core 70 and a resistance wire 80. The core 70 has a rod 71 and two contact caps 72. The rod 71 has two opposite ends. The two contact caps 72 are respectively mounted on the two opposite ends of the rod 71. The resistance wire 80 is wound around a periphery of the rod 71 of the core 70. Two ends of the resistance wire 80 are electrically connected to the respective contact caps 72.
The wire wound resistor is made to have different resistance values by selecting the resistance wire 80 of choices differing in lengths and materials. The resistance wire 80 is electrically connected to external circuit components through the two contact caps 72.
However, the conventional wire wound resistor only targets at serving as a circuit component having a resistance value and connected to the external circuit components in an electronic circuit design without providing any protection to the electronic circuit. As a result, a regular electronic product usually needs a fuse to protect it against burnout arising from abnormal short circuit. Inevitably, the additional fuse increases the cost and size of the electronic product.